Naloxone modulates visual judgments of similarity but not dissimilarity
Cognitive Affective & Behavioral Neuroscience (2013) - Comment
doi: 10.3758/s13415-013-0155-9  issn: 1530-7026  issn: 1531-135x  pubmed: 23494456 

Peter Krummenacher, Elvan Kut, Gerd Folkers, Peter Brugger